We did this one straight after Bridge Over Troubled Water 3 in Dorking. That one was rated 5/5 but we knew this one would be harder as it was by Cache U Nutter.
There was an ominous "Deep Water" sign across from where we'd parked, but fortunately it hadn't rained too much recently and the water level wasn't too high. The Bobcat decided that he'd wear his snorkel anyway.
I led the way into the tunnel as I had the big torch, The Bobcat next with a small wind-up one and Mr and Mrs Richiecactus in the rear with just a head-torch between them. The walk was a lot longer than I'd expected, and the second section got quite slippery, but the cache was an easy find.
We took some pictures to record the event. Great fun. I usually concentrate on doing puzzles but I quite fancy doing some more extreme caches now.